I’m not familiar with those brand of jeans, but “hairy” and “slubby” (and “nep”) mean different items.Greg, I think the fibers you are referring to are known as "Slub" or "slubbyness" it has to do with how the denim was processed ( But really how it hasn't been processed) as that hair is often seared off with heat in modern manufacturing. were they advertised as "Raw Denim"?
Hairy – Seen on unfinished or “loomstate” denim, where excess cotton fibers are seen on the denim surface. I don’t know if that is what is seen here or simply not well finished.
Slub – The thread thickness is varied along the thread and sometimes different average thickness “slubby” threads are woven together to make a slubby fabric. Slubby denim kind of feels like a Triscuit cracker. As the horizontal weft is normally not dyed, slubby denim fades along the vertical warp and at different rates, depending upon the varying thread diameter. This makes for very dramatic fades not seen in usual denim (example at end).
Nep – Cotton fibers, usually broken, protrude from the surface of the denim.
An example of faded slubby jeans...